In the current network structure of telecom operators, optical devices are used to make physical transmission networks, and data devices, as user-layer devices, are connected to the optical devices. The connection between data devices is implemented through a physical channel of the optical devices. Data devices such as routers are connected with network devices such as optical devices through a User Network Interface (UNI), and the link between a data device and a network device is a UNI link.
Common UNI types include: Ethernet interface, Packet over SDH/SONET (POS) interface (a mapping interface for transmitting packets on SDH/SONET), and Optical Transport Network (OTN) interface, where SDH/SONET is short for Synchronous Digital Hierarchy/Synchronous Optical Network. The common rates of an Ethernet interface are 1 Gbps, 10 Gbps, and 100 Gbps which is being defined by standardization organizations; the rates of a POS interface are 155 Mbps, 622 Mbps, 2.5 Gbps, 10 Gbps, and 40 Gbps; and the rates of an OTN interface are 2.5 Gbps, 10 Gbps, 40 Gbps, and 100 Gbp which is being defined by standardization organizations.
The data devices are primarily capable of forwarding the packets from the link layer or the network layer through a proper port according to the routing algorithm; and the optical devices are capable of configuring cross connections on the physical channel layer according to service requirements, selecting a corresponding port and extending the cross connections to other optical devices through fibers.
Link aggregation is put forward in the IEEE 802.3ad, and refers to combining two or more data channels into a single channel which appears as a single logical link of higher bandwidth. Link aggregation generally meets requirements of high-bandwidth connections, and protects ports in a group through redundant physical ports. The main idea of the technology of link aggregation is to allocate Media Access Control (MAC) addresses of all physical ports in a group to a same network layer port, namely, multiple ports have only one Internet Protocol (IP) address and only one destination IP address. Such physical ports are configured as a trunked port, and connected with a corresponding trunked port on the opposite side, therefore an aggregated link is formed.
As shown in FIG. 1, the physical ports D1-P1 and D1-P2 of the data device 101 are configured as a trunked port; the physical ports D2-P1 and D2-P2 of the data device 102 on the opposite side are configured as a corresponding trunked port. A physical link is formed between the physical port D1-P1 of the data device 101 and the physical port D2-P1 of the opposite data device 102, and another physical link is formed between the physical port D1-P2 of the data device 101 and the physical port D2-P2 of the opposite data device 102. The physical links between trunked ports of the two data devices forms an aggregated link. So that an aggregated link is actually composed of two physical links. When one of the physical links fails, the other physical link works instead to bring a protective effect. The two physical links have the same source and the same destination, namely, the two physical links have the same source IP address and the same destination IP address.
The link aggregation in the prior art is defective in: because two physical links directed to the same destination need to be bound together to bring a protective effect, the UNI links directed to different destinations cannot be protected; and single-layer network protection does not prevent the UNI link failure from affecting the whole network. With the growth of network bandwidth, the port capacity is increasing, and the telecom operators impose higher and higher requirements on network reliability, Quality of Service (QoS) of the data service, network expansion, and initial construction costs. Therefore, the prior art cannot meet the operator's requirements on networks.